The present invention initially relates to a method for extracting water from a washload, particularly in the commercial laundry field.
In commercial laundries, washing takes place essentially continuously by passage of the items being washed through so-called counterflow washing machines in which fresh water is added at the end of the machine for rinsing the laundry. From there, the fresh water then flows, increasingly loaded with dirt, through the main washing and prewashing zones. The fresh water is heated, particularly in the main washing zones, by directly blowing in steam, for which purpose the saturated steam pressure of approximately 10-13 bars, as it is usually employed in laundries, is reduced to about 3-5 bars, so as to prevent unnecessary noise development due to the otherwise high speed of the steam when entering into the stationary water baths. In any case, the existence of pressurized steam and its use as the heating means during work in the actual laundering process is an important factor for the present invention.
The extraction of water from rinsed laundry is generally effected by means of friction rollers, presses or centrifuges whose operating speed is limited and which require additional energy for their drives. In the diaphragm presses presently mainly used for water extraction, the residual moisture increases suddenly when a pulse time of 2 minutes is not reached. The energy consumption for driving such diaphragm presses is very high, and the investment costs for making available the driving current are correspondingly high.